The present invention relates to a drive system for a motor vehicle, in particular a motor vehicle with hybrid drive.
Hybrid drives are the combination of different drive principles or different energy sources for a drive task within an application. Motor vehicles with hybrid drive, also called hybrid vehicles, comprise for example an internal combustion engine and an electric machine. The electric machine is usually embodied as a starter-generator and/or an electric drive. As a starter generator it replaces the normally available starter and the generator. When embodied as an electric drive an additional torque, i.e. an acceleration torque, to advance the vehicle can be contributed by the electric machine. In its function as a generator it enables a recuperation of the brake energy. Furthermore, hybrid vehicles comprise at least one energy accumulator. The energy from the energy accumulator can be used for starting the internal combustion engine, for the electric consumers in the vehicle and for acceleration processes. During driving the energy accumulator is fed via the generator by the internal combustion engine. In addition, the energy accumulator is charged by energy recuperation during braking. Via a control electronics the different modes are controlled, inter alia as to whether energy is to be drawn from or supplied to the energy accumulator.
From EP 0 913 287 A2 a hybrid vehicle is known, which comprises a machine to advance the hybrid vehicle. The machine has an output shaft, a power transmission means for transferring an output power of the machine from its output shaft to the driving wheels as well as an electric motor for supplying a support output power for supporting the output power of the machine by the power transmission means to the driving wheels. Furthermore, a current energy storing means is provided to store electric energy and to excite the electric motor and a vehicle operation control means to control/regulate the operation of the hybrid vehicle with the machine and the electric motor. The vehicle operation controlling means comprises a means for controlling/regulating the electric motor for producing the support output power, to be able to start the hybrid vehicle with the electric energy, which is supplied to the electric motor by the current energy storage means, while the machine coasts, if the electric energy quantity stored in the current energy storage means is larger than a given value. Finally, means are provided to control/regulate the machine, in order to effect that the output shaft produces an output power for starting the hybrid vehicle, while the electric motor is excited, if the electric energy quantity stored in the current energy storage means is smaller than the give value.
It is the object of the invention to further embody in advantageous manner a drive system for a motor vehicle according to the state of the art.